/*
 * Copyright (c) 2011-2012 Alexander Dubu
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * o  Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * o  Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * o  Neither the name Axil nor the names of its contributors may be used to
 *    endorse or promote products derived from this software without specific
 *    prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package axil.vm.opcode;

import axil.api.AxilObject;
import axil.api.extend.Environment;
import axil.api.extend.Function;
import axil.api.extend.Parameters;
import axil.api.extend.Source;
import axil.vm.stack.IDedArguments;
import axil.vm.stack.StackFrame;

import static axil.framework.Functions.debug;
import static axil.framework.Functions.replace;


/**
 * Call a function, but call it with lazy evaluation. The arguments are not
 * evaluated here, but conditionally in the function.
 */
public class OpCallLazy extends OpCall implements IDedArguments {
	private Function func;
	private int[] ids;
	private AxilObject[] args;


	public OpCallLazy(Source source, Function func, int[] ids,
	                  AxilObject... args) {
		super(source);
		this.func = func;
		this.ids = ids;
		this.args = args;
	}


	/**
	 * Get the array of IDs representing the unique ID of each argument to a
	 * function. The array returned is never null but may be empty.
	 */
	public int[] ids() {
		return ids;
	}


	/**
	 * Relink this instruction, replacing the bad variable ID with the good
	 * variable ID. This is used when linking code that contains forward
	 * references, allowing us to compile in a single pass, but correct later.
	 */
	public void relink(int bad, int good) {
		replace(ids, bad, good);
		replace(args, bad, good);
	}


	/**
	 * Dump the content of this node to the diagnostic device. This is strictly
	 * for internal diagnostics, not for application use.
	 */
	public void dump(int indent) {
		debug(indent, "CALL(lazy) - " + func.getClass().getSimpleName());
		indent ++;
		debug(indent, "ARGS:");
		indent ++;
		for (AxilObject arg : args) {
			((Opcode)arg).dump(indent);
		}
	}


	/**
	 * Evaluate this object in the given context and environment. A non-null
	 * object must be returned.
	 */
	protected AxilObject evaluate(Environment env, Parameters params) {
		StackFrame sf = StackFrame.create(params, this, ids, args);
		int i = 0;
		for (AxilObject arg : args) {
			sf.at(i, arg);
			i++;
		}
		return func.eval(env, sf, this);
	}
}
